/* /* let obj = {
    1:0,
    2:1,
    3:2,
    1:3,
    2:4
}
console.log(Object.keys(obj)); */
/* let arr = [1,2,3,1,2]
function unique(arr){
    let obj ={

    }
}  */
let arr = [1,2,3,1,2]
function unique(arr){
    let obj ={}
    return arr.filter((item,index,array)=>{
        return obj[item]?false :(obj[item]=true)
    })
}
console.log(unique(arr));
